Optical gain at 1.55 µm of Er(TMHD)₃ complex doped polymer waveguides based on the intramolecular energy transfer effect

Abstract

Based on the intramolecular energy transfer mechanism between organic ligand TMHD (2, 2, 6, 6-tetramethyl-3, 5-heptanedione) and central Er3+ ions, optical gains at 1.55 µm were demonstrated in three structures of polymer waveguides using complex Er(TMHD)3-doped polymethylmethacrylate (PMMA) as the active material. With the excitation of two low-power UV light-emitting diodes (LEDs) instead of 980 or 1480 nm lasers, relative gains of 3.5 and 4.1 dB cm-1 were achieved in a 1-cm-long rectangular waveguide with an active core of Er(TMHD)3-doped PMMA polymer. Meanwhile, relative gain of 3.0 dB cm-1 was obtained in an evanescent-field waveguide with cross-section of 4 × 4 µm2 using passive SU-8 polymer as core and a ∼1-µm-thick Er(TMHD)3-doped PMMA as upper cladding. By growing a 100 nm thick aluminum mirror and active lower cladding, the optical gain was doubled to 6.7 dB cm-1 in evanescent-field waveguides because of the stimulated excitation of Er3+ ions in the upper and lower cladding and the improved absorption efficiency.

Phosphine Oxide-Nd3+ Coordination Chains with Cumulated Output Enable Efficient LED-Pumping Optical Amplification

“…In contrast, organic ligands can protect lanthanide ions from intermolecular interactions and improve processability of the complexes. − In particular, organic ligands can sensitize lanthanide ions through Förster resonance (FRET) and Dexter (DET) energy transfer from their first singlet (S 1 ) and triplet (T 1 ) excited states, respectively. This so-called ligand “antenna effect” allows lanthanide complexes to take use of ultraviolet (UV) and deep-blue light in the range of 200–450 nm for near-infrared (NIR) emissions, which actually establishes the basis for NDWAs using low-power UV-blue light-emitting devices (LEDs) as pump sources .…”